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Thinking small

A prototype for a new proton-exchange membrane fuel cell sits on the lab bench in the WPI Fuel Cell Center.

Tomorrow's electric power production and distribution network may look very different from today's, with smaller, more environmentally friendly power plants supplanting large, central generating stations. Among the technologies that will help bring this vision to reality are two (wind energy and fuel cells) that are being advanced by faculty members and students at WPI.

By Laurance S. Morrison and Michael W. Dorsey, Photography by Patrick O'Connor

Call it a micro-revolution.

For over a century, electric power systems have been designed for economies of scale, with large fossil-fuel or nuclear generating plants producing electricity and delivering it through far-flung grids of transmission lines to homes and businesses many miles away. It's a system that has worked reasonably well through the years, despite its vulnerability to natural events, technological glitches and acts of terrorism.

But as the Information Age has made every aspect of modern society increasingly dependent on highly reliable supplies of electric power, as consumers have grown increasingly reluctant to support energy policies that tax the environment, finite natural resources or human health, and as recent power crises, like those in California, have made clear the complexities of managing vast interconnected power networks, a new paradigm of energy production and distribution has begun to emerge.

In this new model, power generation is dispersed, with smaller, more environmentally friendly sources of electricity located closer to where the power is needed. Sophisticated networks monitored by high-tech sensors and intelligent agents control the flow of watts and account for the movement of dollars in this "smart" energy marketplace.

One of the advocates for this new model is the Electric Power Research Institute, the electric power industry's own research and development think tank. A story in the July 2001 issue of Wired magazine notes that EPRI envisions smarter energy networks that "will incorporate a diversified pool of resources located closer to the consumer, pumping out low- or even zero-emission power in backyards, driveways, downscaled local power stations, and even in automobiles, while giving electricity users the option to become energy vendors."

The new focus on smaller and cleaner sources of electric power has placed a spotlight on alternative electric power generation technologies, including two (wind turbines and fuel cells) that are the focus of research and student project work at WPI.

Stephen W. Pierson, associate professor of physics and a theoretical physicist specializing in condensed matter, has been doing research on wind power, largely through several student projects exploring one of the oldest forms of small-scale power generation. Fundamental research under way in WPI's Fuel Cell Center, a university-industry alliance headed by Ravindra Datta, professor and head of the Chemical Engineering Department, is putting research teams of graduate students and undergraduates to work to advance the state of the art in fuel cells, which are creating quite a buzz in the electric arena.

Pierson's and Datta's separate but ultimately related research pursuits typify the curiosity, fundamental research, teamwork and practicality--and sense of social responsibility--that make special the WPI brand of education. Think of it as the power of curiosity.

"Engineers," Datta says, "can assist society in improving the standard and quality of life here and in the rest of the world. Energy offers special opportunities because the planet is operating on a course that will eventually deplete the known fossil fuel resources, perhaps even in the next 50 years."

As living conditions improve and the earth's population burgeons, the result will be ever-higher energy consumption. The scenario cries out for a reasoned and sustainable plan of action, Datta says.

WPI students can help write that plan through graduate research and, at the undergraduate level, through their required projects. The Interactive Project thrusts students into practical problems that lie at the intersection of science and technology. In typically three-member teams, they work toward solutions.

"This isn't textbook work," notes Pierson, who has advised 28 Interactive Projects on topics ranging from Worcester traffic to the Iraqi missile program. "We talk, we analyze, we question, we test the quality of the data, we press for strong spoken and written communications. We isolate the careless generalization, point out the unsubstantiated conclusion, and expect precision in each project."

Helping students achieve those outcomes is a fine art, Datta says. "We must know when to provide guidance to a student and when to hold back. Especially with graduate students, we find that after they finish their course work and are pursuing their research, they soon wind up knowing more about their chosen topics than we do. And they are thinking independently. This is good. In fact, we learn along with them, and the relationship blossoms from teacher-student to colleagues. To be a good teacher, you first have to be a good student."

Blowing in the Wind

Stephen Pierson

Acknowledging that a sustained investigation of wind energy as a practical energy resource lies some distance from his work in condensed matter, Pierson, shrugging contentedly, explains that he hails from North Dakota, "the windiest state. I've long had an interest in energy issues and challenges, and I've been looking to make my research more socially relevant."

Wind turbines currently generate less than 1 percent of the electricity consumed in the United States (compared with about 80 percent for coal, oil and natural gas), or about 3,500 megawatts per year. That output has been steadily rising as the cost of generating electricity with the wind has continued to drop and as utilities have come to see this once fringe energy source as a viable alternative to conventional power plants. "Wind, under the right circumstances, can be cheaper than coal," Pierson explains, "and wind is inexhaustible."

He says that there are three central factors that can turn wind generation into a competitor for electricity produced with coal and natural gas. "The wind must be sufficiently strong and sustained," he says. "The turbines should be grouped in large farms to reap the benefits of the economy of scale. And the developer should take advantage of the federal governments' Production Tax Credit."

While wind turbines consume no fuel and produce no pollutants, they are not without environmental impacts. Some communities have objected to wind farms within their boundaries because of the visual impact of the tall turbines and because of the noise they make. Design refinements have reduced the noise produced by turbine blades and care taken in the design of farms can often reduce aesthetic concerns.

Wind farms also need to be close to transmission lines and power grids. The need for more transmission line capacity, he noted, has made odd allies of coal interests and the wind farm industry, which rallies under the American Wind Energy Association.

Not yet mainstream in the United States, wind energy (the fastest growing reusable energy source worldwide) is meeting less than 1 percent of the electricity needs of Princeton, Mass., several miles north of the WPI campus. New England's largest wind farm is situated in Vermont, and by the scale of many European installations it is modest in size and output.

Pierson will soon begins a year's sabbatical during which he expects to pursue public affairs issues for the prestigious American Physical Society. The direction of his sabbatical underlines the bedrock WPI idea of the integration of technology and social consequences.

Last year, in an op-ed piece published in the Worcester Telegram & Gazette, he spelled out causes for concern, as he saw them, in the shape of the proposed federal energy policy and direction of climate change.

Citing conclusions of the Union of Concerned Scientists, in Cambridge, Mass., where he has served as a visiting scientist, Pierson listed "the gravest consequences of global warming as more extreme weather events, a faster rise of sea level, and more heat waves and droughts that lead to more heat-related illnesses and deaths."

The choice is clear. He wrote, "With options that could save us money, reduce carbon dioxide emissions, and address the other limitations of fossil fuels, why wouldn't we pursue them?"

Making Fuel Cells Practical

"Imagine what the world would be like without widely shared fundamental research."
--Ravindra Datta

Fuel cells convert fuel directly, efficiently and continuously into electricity through electrochemical reactions. Long used as a power source in spacecraft and military vehicles, they are increasingly being eyed as a future source of clean power for homes, businesses and automobiles. They are also frequently cited as a key technology for realizing the vision of tomorrow's distributed power system. It has been estimated that the market for fuel cells could reach $1 billion by 2006.

Most fuel cells use hydrogen as a fuel. The hydrogen splits into protons and electrons on the anode catalyst, typically platinum. The protons pass through a membrane and combine with electrons from oxygen to generate electricity and water. Because they produce extremely clean energy and are twice as fuel-efficient as conventional internal combustion engines, fuel cells are of great interest to automobile makers. In fact, virtually every major car producer has a significant research program focused on fuel cells, and forecasters predict that cars powered by fuel cells could be available to consumers by the end of the decade.

Today's fuel cells tend to be bulky and expensive. And until there are hydrogen filling stations in every town, putting hydrogen-based fuel cells in cars and other consumer applications may not be practical. That is why a number of researchers, including Datta, are studying fuel cells that use other fuels or that can locally convert more conventional fuels into hydrogen suitable for fuel cells.

It is possible to extract hydrogen from gasoline using catalysts, but the resulting hydrogen stream has contaminants, including carbon monoxide, that can poison the fuel cell. To make fuel cells that are more tolerant of carbon monoxide, Datta and his students are working to develop more robust electrode catalysts and proton-exchange membranes for fuel cells. Nafion, a polymer membrane made by Dupont, is currently the most widely used proton-exchange membrane. To work effectively, however, it must be soaked in water, which limits the fuel cell temperature to 80° C.

Datta and his students are developing proton-exchange membranes that can operate at higher temperatures, which make PEM fuel cells better able to deal with carbon monoxide and other poisons. They have also found that they can maintain the membrane's high ionic conductivity at reduced humidity levels, which increases power output.

The WPI researchers are looking at other ways to take on the temperature-humidity issue. They are examining higher-temperature inorganic membranes and composite organic-inorganic membranes. They are also developing new catalytic electrode materials that are more robust than the conventional platinum.

Research in the Fuel Cell Center is also focusing on using watery ethanol, a renewable organic fuel made from biomass, as a fuel. Watery ethanol is less expensive to produce than fuel-grade ethanol, and can produce a clean stream of hydrogen in a reformer heated to about 500° C. PEM fuel cells powered by hydrogen produced from ethanol hold the promise of producing electricity in a highly efficient, sustainable and environmentally sensitive manner.

Datta says one of the goals of the Fuel Cell Center is to see the breakthroughs that occur in the laboratory make their way as soon as is practical into socially useful applications. "We don't hold back in widely disseminating our latest research findings," he says. "We publish our work promptly. Imagine what the world would be like without widely shared fundamental research. This basic tenet of universities is really quite a concept, one that has a profound influence on humanity."

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